/// <summary>
/// Decrypts the key and returns the decrypted buffer.
/// </summary>
/// <param name="buffer">The key to decrypt.</param>
/// <param name="offset">The offset to start the decryption at.</param>
/// <returns></returns>
private static void Decrypt(byte[] buffer, int offset)
{
// First decrypt the key
SecurityEncryption.Decrypt(buffer, offset);
// Then XOR the entire array with the salt
for (int i = (offset + 2); i < (offset + 24); i += 2)
{
buffer[i] = (byte)(buffer[i] ^ buffer[offset]);
buffer[i + 1] = (byte)(buffer[i + 1] ^ buffer[offset + 1]);
}
}
/// <summary>
/// Encrypts the key and returns the encrypted buffer.
/// </summary>
/// <returns>Encrypted buffer.</returns>
private byte[] Encrypt()
{
// The buffer for encryption
var buffer = new byte[24];
buffer[0] = this.Buffer[this.Offset];
buffer[1] = this.Buffer[this.Offset + 1];
// First XOR the entire array with the salt
for (int i = 2; i < 24; i += 2)
{
buffer[i] = (byte)(this.Buffer[this.Offset + i] ^ buffer[0]);
buffer[i + 1] = (byte)(this.Buffer[this.Offset + i + 1] ^ buffer[1]);
}
// Then encrypt the key using the master key
return(SecurityEncryption.Encrypt(buffer));
}
/// <summary>
/// Decrypts the license with the public key.
/// </summary>
/// <param name="data"></param>
/// <param name="keySize"></param>
/// <returns></returns>
public static SecurityLicense LoadAndVerify(string data)
{
try
{
// We should have the data
if (String.IsNullOrWhiteSpace(data))
{
throw new SecurityLicenseException("No license was found, please provide a valid license key through the configuration file, an EMITTER_LICENSE environment variable or a valid vault key 'secrets/emitter/license'.");
}
// Load the license
Current = new SecurityLicense(
Base64.UrlEncoding.FromBase(data)
);
// Expired?
if (DateTime.UtcNow > Current.Expires && Current.Expires > new DateTime(2000, 1, 1))
{
throw new SecurityLicenseException("The license file provided has expired.");
}
// Set the encryption key for the service
SecurityEncryption.SupplyKey(Current.EncryptionKey);
// Return the license now, but scramble the encryption key
Current.EncryptionKey = null;
return(Current);
}
catch (SecurityLicenseException ex)
{
// We do not return an exception, as the license is invalid anyway
Service.Logger.Log(LogLevel.Error, ex.Message);
return(null);
}
catch (Exception)
{
// We do not return an exception, as the license is invalid anyway
Service.Logger.Log(LogLevel.Error, "Invalid license was provided, please check the configuration file or use EMITTER_LICENSE environment variable to provide a valid license key.");
return(null);
}
}